Where are kids going to play
Archmages Charm is extremely pushed, a solid permission spell, a good way to build card advantage for hitting land drops, and a fantastic tool against Deaths Shadow, Wild Nacatl, Goblin Guide, Pyxis of Pandemonium, Champion of the Parish, Aether Vial, Delver of Secrets, Hardened Scales, Amulet of Vigor, Benthic Biomancer, Glistener Elf, Noble Hierarch, Viscera Seer, and sometimes even Hexdrinker (just to mention a few)
As I already mentioned, there are nine card types that you can put into a deck, meaning that the biggest a Tarmogoyf can get on its own is 9/10
As a rule of thumb, the balance of card types in your deck should align with your overall strategy